When trying to upload profile picture, it is not being saved

[r_beat]

Hi everyone!
I have the following issue:
When I try to update a profile pic in Teams (no matter from where: Desktop app, Web app, Phone app), it does not stay there.
It successfully uploads (no errors are being shown) and even shows up in the preview, but when I check it again - it defaults back to "two letters" one. My teammates do not see changes either. Screenshots from mobile app included.

I'm using free version w/o Microsoft account (signed up during free plan selection).

Anyone has a clue of what's going on?

[#2]

Verificación del el archivo que intentas cargar, puede que no cumpla los parámetros admitidos

[#3]

I've tried using different pictures, they just do not stay there. Additionally, no errors are being shown.

[#4]

@r_beat UPDATE! When trying to update the photo from browser, the following errors are being shown in DevTools console: